Conventional tube benders are commonly used for bending tubes, classified into a pull-style and a push-style ones. The pull-style tube bender is provided with a worktable, a control device fixed on the worktable, a tube pushing device positioned on the worktable to move longitudinally, and a pull-style bending device positioned on an end of the worktable. In bending a tube, a tube being bent has its one end clamped tightly in a clamper of the tube-pushing device, and its other end facing toward the tube-bending device. Then the tube being bent is moved in a preset speed by the control device to the tube-bending device. Subsequently, the control device commands a driving unit of the tube-bending device to bend the tube being bent into the preset shape by pulling the bending mold in conjunction with a guide mold.
However, the processes of bending by pulling may easily cause clamping scars and disfiguring to result in disqualified products, because the tube being bent is clamped by the roller unit of the bending device and then clamped by the bending unit of the bending device for carrying out bending action.
A conventional pushing-style tube bender disclosed in an Italian patent No. 1291332 includes a worktable, a controlling device provided on the worktable, and a tube pushing device fixed on the worktable to move longitudinally, au auxiliary pushing device added to the tube pushing device, and a push-style bending device fixed on one end of the worktable. In bending a tube by this tube bender, a tube being bent has its one end clamped by a clamper of the tube pushing device, with the other end facing to the push-style bending device. Then the controlling device commands the tube pushing device to move the tube in a preset speed to the bending device, and then commands the driving unit of the bending device move a bending mold to a preset location of a guide mold, letting the auxiliary pushing device of the tube pushing device push the tube to the bending mold with a large force. Then the bending mold and the guide mold bends the tube into a preset shape by mutual sidewise pushing.
Though the case of the Italian patent can improve the drawback of easy disfigure of a tube after bent, the tube is not actually contact completely to the roller mold of the guide mold in performing bending action, so it is not easy to control the size of the tube after bent, still not so well qualified for producing perfect bent tubes.